Dipstick actuated illuminating device



April 24, 1956 E. w. GILBERT DIPSTICK ACTUATED ILLUMINATING DEVICE Filed Nov. 10, 1953 I N VENTOR 171w fli/Jeri ATTORNEYS United States Patent 2,743,352 DIPSTICK ACTUATED ILLUMINATING DEVICE Elma W. Gilbert, Philpot, Ky. Application November 10, 1953, Serial No. 391,244 1 Claim. (Cl. 240-7.1)

This invention relates to means for illuminating that region of the internal combustion engine of an auto vehicle in the vicinity of the crankcase dipstick, so that in servicing the engine for oil at night, the dipstick can be inspected close to the dipstick tube, and the latter be made discernible to facilitate reinsertion of the dipstick.

The general object of the invention is to provide a dipstick actuated switch in circuit with a. lamp, the latter being positioned near the dipstick, the switch having an inherent closing bias, being held open contra to said bias when the dlpstick is in place, and released so as to exercise its closing bias, responsive to the removal of the dipstick, thereby lighting the lamp.

Another object of the invention is to provide a unitary cluster comprising a rigid base on which the switch, lamp, and circuit connection between the switch and lamp, are mounted, said base carrying means for connecting it about the dipstick tube, and having a passage therethrough through which the dipstick passes, the switch being held open by the dipstick when in place, and closing responsive to the removal of the dipstick.

Other objects of the invention will appear as the following description of a practical embodiment thereof proceeds.

In the drawing throughout the figures of which the same reference characters have been used to denote identical parts:

Figure 1 is a view in side elevation of a device embodying the principles of the invention, attached to the dipstick tube of the internal combustion engine;

Figire 2 is a longitudinal vertical section taken along the line 22 of Figure 3;

Figure 3 is a horizontal sectional view taken along the line 3-3 of Figure 1.

Referring now in detail to the drawing, the numeral 1 represents the engine of an auto vehicle having the dipstick tube 2 communicating with the crankcase, and the dipstick 3 sheathed within the tube, frictionally engaging the same and extending into the crankcase to a point below normal oil level. The dipstick is shown with a flange 4, which in conventional use limits the extent of insertion of the dipstick and forms a cover for the dipstick tube. At night when the engine is serviced for oil it is ordinarily necessary to employ a flashlight to locate the dipstick tube, which is inconvenient, since the attendant needs both hands for wiping the dipstick before reinserting it to ascertain the existing oil level. He is often obliged to take the dipstick to a lighted area of the service station to inspect it, and frequently he fishes for the dipstick tube in the dark, with the end of the dipstick, collecting dust and grit upon it which is finally thrust into the crankcase.

The present invention as illustrated comprises a base block 5 of insulation material having an annular metal collar 6 fixed to its under side adjacent one end. Said collar fits about the end of the dipstick tube, being suitably secured as by the set screw 7. The base block has a hole 8 therethrough in registry with the bore of the collar, through which hole the dipstick extends.

At its opposite end, the base block carries on its upper side a lamp socket 9, fixed to the end of a tubular post 10, which extends through the base block and is secured by a nut 11 screwed to the end of the post, the latter being in electrical contact with the shell of the lamp socket. An insulated wire passes through the post connecting the central terminal of the lamp socket to the hot side of the battery of the auto vehicle.

A switch is interposed between the post 10 and the collar 6. Said switch comprises a fixed contact 12 secured to the under side of the base block and connected to the collar by a metallic strip 13 which is grounded on the collar, and movable contact consisting of a resilient metal blade 14 connected to the post and being biased so as normally to engage the fixed contact 12. The blade 14 is deflected so as to pass freely upward through a hole 15 in the base block and has a free end portion 16 in spaced relation to the upper side of the base block extending toward the hole 8 and terminating adjacent said hole so as to be overlain by the flange 4 of the dipstick. The end portion 16 is covered with insulation material 18 to keep the switch from being grounded through the dipstick.

When the dipstick is inserted to its full depth in the dipstick tube, the flange 4 presses the end portion 16 of the blade 14 down against the base block, thereby opening the switch and holding it open. The lamp 17 which is carried in the lamp socket, will therefore remain unlit while the dipstick is in place. When the dipstick is withdrawn, the end portion 16 is released and the switch closes under its normal resilient bias, lighting the lamp. Thus the region adjacent the dipstick tube is illuminated while the dipstick remains withdrawn, enabling the dipstick to be wiped and inspected in immediate proximity to the dipstick tube, and making the latter discernible to facilitate the replacement of the dipstick.

While I have in the above description disclosed what I believe to be a practical embodiment of the invention, by those skilled in the art that the specific details of construction and arrangement of parts, as shown, are by way of example and not to be construed as limiting the scope of the invention.

What I claim is:

Switch and lamp socket unit for illuminating that region of an auto vehicle engine compartment adjacent the crank case dipstick tube, comprising a conductive clamp collar for surrounding the dipstick tube in attachment thereto, an elongated base block of insulating material secured at one end to said collar having a hole therethrough coaxial with the bore through said collar forming a passage for a dipstick, said base block having an electric lamp socket at its opposite end and having a hole therethrough at a point intermediate its ends, means providing a hot battery connection to one pole of said lamp socket, a normally open switch in series circuit with said lamp socket comprising a fixed contact carried by said base block exposed on its under side, and a resilient switch blade connected to the opposite pole of said lamp socket having a switch closing bias, underarching said fixed contact in operative proximity thereto, passing freely upward through said intermediate hole and having its free end adjacent said dipstick passage, adapted to be normally depressed by a seated dipstick contra to its switch closing bias.

References Cited in the file of this patent UNITED STATES PATENTS 2,010,390 Duncan Aug. 6, 1935 2,258,685 Mattlatzki Oct. 14, 1941 2,604,557 Nelson July 22, 1952 2,658,989 Marschat Nov. 10, 1953 FOREIGN PATENTS 587,075 Great Britain Apr. 14, 1947 

